Maitake mushroom named ‘Grifon-7’

ABSTRACT

The present variety of mushroom plant named ‘Grifon-7’ was cultivated by the collecting and repeated breeding of Maitake mushrooms having dominant traits, which has good qualitative characteristics and appearance, thick color at the cap surface, white color at the back side of the cap, and excellent cultivability and high yields. This edible mushroom is exquisite in stability, reproducibility and uniformity when being produced.

BACKGROUND OF THE INVENTION

This invention relates to a new and distinct variety of mushroom plantof Maitake mushroom, Grifola frondosa (Fr.) S. F. Gray. This new varietynamed ‘Grifon-7’ cultivated by repeated breeding of Maitake mushroomshaving dominant traits, which has thick color of cap surface, whitecolor of back side of cap, excellent cultivability and high yield andensure presentable stability, reproducibility and uniformity.

Maitake has been artificially cultured and eaten in Japan since longtime. The extract of Maitake obtained by hot water extraction containsingredients that are effective in treatment of cancer because of whichthere is a great demand of it as a supplement. The demand of freshMaitake is also increasing. In order to promote the sales of freshMaitake, it is required that the variety can be cultured easily and theproductivity improves. Good external appearance of mushroom, taste,storage characteristics are also important factors to make it appealingto consumers. Although Maitake has been cultured by isolating the strainfrom the wild variety, however, it has been unsuccessful to artificiallycontrol the culture environment that suits the culture of Maitake,because of which it could not be produced in a large scale.Consequently, a new variety called ‘Hokuto NT-100’, which is easy toculture and has improved quality, taste and storability, was developedas a result of repeated improvements through cross-breeding to improvethe stability of culture and quality of mushrooms. This variety has beenpatented in US (U.S. Plant Pat. No. 17,984 P3). However, the under-faceof the cap of the Hokuto NT-100 stained easily which made it look lessfresh. Thus, the quality of its appearance was identified as a weakness.To overcome this weakness of Hokuto NT-100, cross-breeding wasrepeatedly conducted as a result of which a new variety named‘Grifon120’ that has a white under-face of cap was developed and havingU.S. Plant Pat. No. 21,575. However, it was pointed out that Grifon120has thin color at the top surface of its cap, because of which it lookedless fresh. Consequently, new varieties were developed, from which a newvariety was selected and named as ‘Grifon-7’ after confirming itsstability, reproducibility and uniformity.

SUMMARY OF THE INVENTION

The present invention is a new and distinct variety of mushroomcharacterized particularly by its good qualitative character andappearance, thick color of cap surface, white color of back side of cap,excellent cultivability and high yield, which can be cultivated bycollecting and repeated breeding of fungal strains having dominanttraits and is exquisite in stability, reproducibility and uniformitywhen being produced. This novel and distinct variety of mushroom isidentified as ‘Grifon-7’.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B respectively show front and back images of dual-cultureof Grifon-7 (G110537) colony.

FIGS. 2A and 2B respectively show front and back images of dual-cultureof Grifon-7 (G110537) and Grifon120.

FIGS. 3A and 3B respectively show front and back images of dual-cultureof Grifon-7 (G110537) and Hokuto NT-100.

FIGS. 4A and 4B respectively show front and back images of dual-cultureof Grifon-7 (G110537) and Hokuto MY-95.

FIG. 5 shows image of fruit body of Grifon-7 (G110537).

FIG. 6 shows image of fruit body of Grifon120.

FIG. 7 shows a phylogenetic tree illustrating the antecedents of Grifon120 and Grifon-7.

DETAILED DESCRIPTION OF THE INVENTION

The history of the Grifon-7 mushroom in terms of improvement period andthe like are set forth in the following chronological list of each stageof variety improvement:

-   January 1993: Cultivation of Hokuto MY-95.-   September 2002: Collected wild Maitake, isolated hyphae and    developed strain No. MH182099 in Yamagata of Japan.-   February 2004: Hokuto MY-95 and MH182099 were crossed, and the    strain having white underface of cap was picked and developed as    MH182188.-   June 2006: Hokuto NT-100 and Hokuto-carrying strains were crossed,    and the strain having thick meat was picked and developed as    MH182238.-   October 2007: Collected wild Maitake, isolated hyphae and developed    strain no. MH182215 in Iwate Prefecture of Japan-   December 2007: Obtained MH182239 by crossing MH182188 and MH182238.-   February 2011: Obtained MH182242 by crossing Hokuto MY-95 and    MH182215.-   December 2011: Obtained an excellent strain named G110537 by    crossing MH182239 and MH182242.-   June 2012: Culture test of G110537 was repeatedly conducted and the    distinguishability, stability, reproducibility and uniformity were    confirmed, upon which the strain was named “Grifon-7” and    cultivation was completed.

October 2012: Applied for registration of new variety to Ministry ofAgriculture, Forestry and Fisheries of Japan. On the other hand, Grifon120 is obtained by crossing MH182188 and Hokuto NT-100, and therefore,Grifon-7 was not developed from Grifon 120. The above crossing issummarized in the phylogenetic tree illustrated in FIG. 7.

The Grifon-7 mushroom has the following characteristics: thick color ofcap surface (199A (Grey-Brown Group)), white color of back side of cap(NN155B (White Group)), excellent cultivability and high yield.

(1) Comparison by Dual Culture with Existing Variety

Dislike-touch reaction between Grifon-7 and similar varieties wasstudied by dual culture.

Study Method:

Grifon-7 and another strain were co-inoculated with an interval of 3 cmby using potato dextrose agar culture medium. Then, the presence/absenceof dislike-touch reaction was determined by culturing for 21 days at 25°C.

Strain Used:

Grifon-7 (G110537) Present variety Grifon120 Varieties similar to thepresent variety Hokuto NT-100 Varieties similar to the present varietyHokuto MY-95 Varieties similar to the present variety

Results:

Grifon-7 showed dislike-touch reaction with all other co-culturedvarieties (See Table 1 and FIGS. 1 to 4). These results show that thepresent strain is a new variety.

TABLE 1 Results of dual culture Similar variety Grifon-7 Grifon120NT-100 MY-95 Grifon-7 − + + + + is present and − is absent.(2) Cultural Characteristics of Grifon-7

When Grifon-7 was cultured in potato dextrose agar culture medium,hyphae color was white, hyphal density was medium, shape of colonyperiphery was heterogeneous, thickness was medium, and surface wasisland.

After inoculating a small piece of Grifon-7 measuring 5 mm diameter inpotato dextrose agar culture medium, it was cultured 5-30° C. with 5° C.interval. When the mean mycelial growth rate per day was calculated fromthe mycelial growth of 10-day culture, it was found that the meanmycelial growth rate was the highest at 26° C.

The mycelial growth rate at 10° C. was fast with 1.31 mm/day, while thegrowth of similar variety Grifon120 was slow at 0.56 mm/day. Also,mycelial growth rate at 15° C. was fast at 2.11 mm/day, while the growthof Grifon120 was medium at 1.68 mm/day. The mycelial growth rate at 30°C. was medium at 2.57 mm/day, while the growth of Grifon120 was slow at0.89 mm/day. From the above results, it can be understood that thestrain is clearly different from Grifon120.

(3) Morphological Characteristics Based on an Example of Grifon-7Cultivation

Cultivation Method

(Bag) A polypropylene culture bag (Square-shaped, capacity: 8500-9000cc, mouth diameter: 200×120 mm, height: approx. 440 mm, air filterpresent) was used. Altogether 48 bags were used, and cultivation wasrepeated three times in each in 16 bags.

(Substrate) Sawdust of broadleaf tree, which is mainly beechwood, andcorn bran were mixed in the dry-weight ratio of 75:25, and the mixturewas adjusted to 60%-62% water content. The substrate was filled at therate of 2.5 kg per bag, and was sterilized at high pressure.

(Spawn) Sawdust spawn was used. About 25 cc of the spawn was inoculatedper bag.

(Culture) Culture was conducted under 20° C.-22° C. temperature, 70-75%humidity and 200-500 lux luminosity, and the cultivar that haveprimordia formation are shifted to the growing room.

(Growth) The primordia forming bag-culture was shifted to a 17° C.-18°C. temperature, 90-95% humidity and 500-1500 lux luminosity environmentto promote the growth of primordia. After the primordia grows up to theextent of touching the filter part, the filter part is taken out andgrowth of fruit body is promoted. The mushroom is harvested when thepore on the back side of cap about 2-3 mm from the edge.

Cultivation Results

The characteristics of Grifon-7 cultivated under the conditionsmentioned above, and the specific difference in characteristics with themost similar variety Grifon120 are explained in Table 2 below.

Also, the images of the respective fruit bodies have also been attached.(See FIGS. 5 and 6).

TABLE 2 present variety similar variety Grifon-7 Grifon120 Mycelialgrowth rate 10° C./day 1.31 mm 0.56 mm 15° C./day 2.11 mm 1.68 mm 20°C./day 2.74 mm 2.36 mm 25° C./day 3.29 mm 3.04 mm 30° C./day 2.57 mm0.89 mm Diameter of a cluster on a 20.17 ± 0.91 cm 20.44 ± 1.07 cm bagCap Diameter 30.14 ± 4.98 mm 36.27 ± 5.68 mm Thickness 1.98 ± 0.28 mm2.03 ± 0.27 mm Shape Fan Fan Observe a shape of vertical Level 45 lowerparts section Color of surface 199A 199C (Grey-Brown (Grey-Brown Group)Group) Hardness Medium Medium Shape of zonate spots of the Peripheralpart Peripheral part surface Development part of pore Whole of cap Wholeof cap Tinting of mycelial mat of Absent Absent the surface ofbag-culture Period from inoculation to 36.8 ± 1.38 days 35.4 ± 1.20 daysprimordia formation Period from inoculation to 45.4 ± 1.33 days 44.9 ±0.87 days harvest Optimum temperature for 18-20° C. 18-20° C. fruit bodydevelopment Fresh weight of fruit body 897.3 ± 48.34 g 855.9 ± 34.85 gper 2.5 kg sawdust-based bag-culture Dual culture Dislike-touch reactionof Present colony * The employed color chart is an R.H.S Colour Chartprescribed by the Royal Horticultural Society, England.

What is claimed is:
 1. A new, distinct variety of Maitake mushroom assubstantially illustrated and described in the specification.